The present invention relates to a tool holder for allowing the use of square shanked tooling on automatic screw machines. For convenience, the subject tool holder is hereinafter referred to as xe2x80x9cStick Tool Holder.xe2x80x9d
Traditionally, automatic screw machines of this type use a circular form tool to shape and form the part being made to its correct size.
These circular form tools are a major cost concern when evaluating the profitability of any given job.
The Stick Tool Holder allows the use of standard square shanked lathe tools to be used in place of the circular form tools. The cost of this lathe tool, the Stick Tool Holder, is a fraction of the circular form tool""s cost.
The Stick Tool Holder has a clearance cut which allows work to be done much closer to the collet chuck. The Stick Tool Holder also has taper control of the tool bit without which the tool bit has to be reground to remove any unwanted taper that may exist on the finished part. There is also a cover plate which prohibits spreading of the Stick Tool Holder body due to the clamping pressure holding the tool bit in place.
Accordingly, there exists a need for a reliable, convenient, adjustable holder that allows the use of square shanked lathe tools, carbide tipped or high-speed steel, to be used on automatic screw machines. The subject Stick Tool Holder meets these needs in an economical and mechanically optimized manner.
Several holders for permitting the use of square shanked tooling in an automatic screw machine can be found in the prior art. One such prior art holder, designated the xe2x80x9cKWIK FORM TOOL BIT HOLDER,xe2x80x9d can be seen in FIG. 4. This holder can only accommodate up to a xe2x85x9c inch square tool bit in the Davenport Machine, an exemplary automatic screw machine which is very well known and widely used in the industry. Also, unlike the subject Stick Tool Holder, this holder does not have a cover plate to stop the spreading action caused by the clamping pressure on the tool bit. The holder, instead, has an excessively thick body web between the top and bottom of the tool bit opening to help stop the spreading problem. This thickness, however, creates another problem: doing work close to the collet chuck is difficult at best, and this is very important in small diameter work as the part has a tendency to flex away from the cutting tool causing a taper problem.
Another prior art holder is sold under the designation xe2x80x9cFLAT FORM TOOL CIRCULAR HOLDER.xe2x80x9d This holder can be seen in FIG. 5 and, even though made by a different manufacturer, it suffers the exact same problems as the previously discussed prior art holder.
While prior art devices are to some extent effective in allowing the use of square shanked tools in automatic screw machines in place of traditional circular form tools, there is a definite need for a holder that will allow the use of larger tool bits, will not spread apart due to clamping pressure, will allow close to the collet work and will allow taper adjustment to the tool bit.
The above objects and advantages of the invention are accomplished by a Stick Tool Holder that can be secured in a circle tool receptacle of an automatic screw machine and then allow square shanked lathe tools, carbide tipped or otherwise, to be used.
The Stick Tool Holder has a cover plate which stops the spreading action caused by the pressure of the clamping bolts as they secure the square shanked tool bit in place. Because of this cover plate, the back side of the Stick Tool Holder can be thinned to a minimum and, with a clearance cut, work can be done on parts right next to the collet chuck.
There are two adjusting screws in the cover plate that make contact with the side of the square shanked tool bit. On the opposite side of the tool bit, half way between the two adjusting screws, is the domed head of a rivet mounted in the Stick Tool Holder body. This rivet head allows for a rocking action of the tool bit by the adjustment and tightening of the two screws in the cover plate. This adjustment allows taper control to be accomplished without regrinding of the tool bit.
Accordingly, the major cost of circular form tools and the regrinding of the tools to control taper will no longer be a problem.
The Stick Tool Holder also has the correct locating diameters and the engagement pin for a circle tool receptacle""s (of an automatic screw machine) center fine controlling mechanism, known as the half moon gear.
In summation, there exists a need for a holder that will allow taper control and the use of all the square shanked tooling that is available in the metal working industry to be used on automatic screw machines. The subject Stick Tool Holder meets this need.